Flame-retardant resin composition

ABSTRACT

A blending of a styrenic resin, and a flame retardant comprising a phenolic resin and a phosphazene compound to a polyalkylene arylate-series resin imparts flame retardancy to a polyalkylene arylate-series resin. The phosphazene compound is a cyclic phenoxyphosphazene compound, a linear phenoxyphosphazene compound, or a crosslinked phenoxyphosphazene compound. The obtained polyalkylene arylate-series resin composition has excellent heat resistance and high flame-retardancy without bleeding out the flame retardant.

TECHNICAL FIELD

The present invention relates to a flame-retardant resin compositioncomprising a polyalkylene arylate-series resin and a process forproducing the same, and a shaped article formed with the flame-retardantresin composition.

BACKGROUND ART

A polyalkylene terephthalate resin such as a polybutylene terephthalatehas excellent mechanical and electrical properties, weather resistance,water resistance, and resistance to chemicals and solvents. Such a resinis, therefore, used as an engineering plastic in various purposes suchas electric or electronic device parts, mechanical device parts andautomotive parts. While, the resin is required to be flame-retardantfrom viewpoint of safety as the field of their uses expands. In general,there is known a method for rendering a resin flame-retardant by addinga halogen-series flame retardant composed of a halogen-series(halogen-containing) compound or a halogen-series compound incombination with an antimony-series (antimony-containing) compound tothe resin. However, the halogen-series flame retardant is not preferablefor environmental reasons because the flame retardant sometimesgenerates a large amount of a dioxin-series compound on resolutioncaused by combustion. Therefore, there is proposed a method forrendering the polyester-series resin flame-retardant by using aphosphorus-series (phosphorus-containing) compound as a halogen-freeflame retardant.

Japanese Patent Application Laid-Open No. 168297/1998 (JP-10-168297A)discloses a flame-retardant resin composition comprising a thermoplasticpolyester resin, a polycarbonate-series resin, and an organicphosphorus-series (phosphate-series) flame retardant. Japanese PatentApplication Laid-Open No. 195283/1998 (JP-10-195283A) discloses apolyester resin composition to which flame retardancy is imparted withthe combination use of a phosphoric ester having a specific structure, anovolak-based phenol resin, and an oxide of a specific metal (such asiron, cobalt, nickel or copper) in an adequate amount. Japanese PatentApplication Laid-Open No. 212412/2000 (JP-2000-212412A) discloses aflame retardant resin composition comprising a thermoplastic polyesterresin, a vinyl-series resin, an organic phosphorus-series flameretardant (such as a condensed phosphoric ester) and a glass fiber. Thephosphoric ester-series flame retardant does not comprise harmfulhalogens; however, the flame retardant is inferior to a halogen-seriesflame retardant in flame retardancy, so that it is necessary to add alarge amount of the flame-retardant. The addition of a large amount ofthe flame-retardant brings about bleeding out (blooming) anddeteriorating in mechanical properties of a resin. It is, therefore,impossible to improve both flame retardancy, and mechanical properties.

Moreover, Japanese Patent Application Laid-Open No. 181268/1999(JP-11-181268A) discloses that addition of 1.5 to 15 parts by weight ofa phosphazene compound and 0.5 to 30 parts by weight of a talc and/ormica to 100 part by weight of a resin mixture containing an aromaticpolycarbonate-series resin and a thermoplastic polyester-series resin ina ratio (weight ratio) of 90/10 to 50/50 [the former/the latter] canimpart flame retardancy to the resin mixture. However, such an aromaticpolycarbonate-based resin composition has a problem in resistance tosolvents. In addition, melt-flowability of the resin composition isdeteriorated upon a molding process, and moldability (formability)thereof is adversely affected.

Incidentally, Japanese Patent Application Laid-Open No. 181429/1999(JP-11-181429A) discloses that flame retardancy is imparted to either athermoplastic resin (such as a polyethylene terephthalate, apolybutylene terephthalate and a polycarbonate) or a thermosetting resin(such as a phenolic resin) by using a specific phosphazene compound(e.g., a cyclic phosphazene compound, a linear phosphazene compound, acrosslinked phosphazene compound formed by crosslinking the cyclicand/or the linear phosphazene compound(s) with a specific group) as aflame retardant. However, in the case where flame retardancy is impartedto a polyethylene terephthalate or a polybutylene terephthalate,satisfactory flame retardancy cannot be imparted thereto with thephosphazene compound alone, and in addition, bleeding out of the flameretardant occurs from a shaped article.

Further, Japanese Patent Application Laid-Open No. 302124/1996(JP-8-302124A) discloses a flame-retardant resin composition comprisinga styrenic resin-containing thermoplastic resin (e.g., a resincomposition comprising a styrenic resin and other thermoplastic resin),a phosphazene compound, and a polyphenol compound (phenol resin). Inthis literature, an embodiment using a polycarbonate or a polyphenyleneether as a thermoplastic resin is described. However, the composition isalso insufficient for flame retardancy.

It is therefore an object of the present invention to provide aflame-retardant resin composition being rendered flame-retardant to ahigh level without deteriorating properties of a polyalkylenearylate-series resin, and a process for producing the same.

It is another object of the invention to provide a flame-retardantpolyalkylene arylate-series resin composition in which bleeding out of aflame retardant is inhibited, and a process for producing the same.

It is still another object of the invention to provide a shaped articleto which high flame-retardancy and thermal resistance are imparted.

DISCLOSURE OF INVENTION

The inventors of the present invention made intensive studies to achievethe above objects and finally found that combination use of aphenoxyphosphazene compound and a phenolic resin as a flame retardant,and additional blending of a styrenic resin with the flame retardantsignificantly improve knead-workability (extrudability) on an extruder.Such blending further realizes impartment of high flame-retardancy to apolyalkylene arylate-series resin without deterioration of mechanicalproperties, and extensively suppresses bleeding out of a flame retardantfrom a pellet and a shaped article and improves thermal stability. Thepresent invention was accomplished based on the above findings.

That is, the flame-retardant resin composition of the present inventioncomprises a resin component and a flame retardant;

-   -   wherein the resin component comprises a polyalkylene        arylate-series resin (e.g., a polyethylene terephthalate-series        resin, a polybutylene terephthalate-series resin) and a styrenic        resin, and    -   the flame retardant comprises a phosphazene compound and a        phenolic resin. The phosphazene compound comprises (1) a cyclic        phenoxyphosphazene compound, (2) a linear phenoxyphosphazene        compound, and (3) a crosslinked phenoxyphosphazene compound, as        described below respectively, and others:    -   (1) the cyclic phenoxyphosphazene compound        -   wherein m denotes an integer of 3 to 25, and Ph represents a            phenyl group;    -   (2) the linear phenoxyphosphazene compound        -   wherein X represents the group —N═P(OPh)₃ or the group            —N═P(O)OPh, Y¹ represents the group —P(OPh)₄ or the group            —P(O)(OPh)₂, n denotes an integer of 3 to 10000, and Ph has            the same meaning as defined in the formula (1);    -   (3) the crosslinked phenoxyphosphazene compound which is a        compound formed by crosslinking at least one phenoxyphosphazene        compound selected from the group consisting of the cyclic        phenoxyphosphazene compound (1) and the linear        phenoxyphosphazene compound (2) with at least one crosslinking        group selected from the group consisting of o-phenylene group,        m-phenylene group, p-phenylene group, and a bisphenylene group        represented by the formula (3):        -   wherein A represents —C(CH₃)₂—, —SO₂—, —S— or —O—, and a            denotes 0 or 1, and            wherein the crosslinking group is bonded to two oxygen atoms            with elimination of phenyl groups of the phosphazene            compound(s), and the content of the phenyl group of the            crosslinked compound is, based on the total phenyl groups in            at least one phosphazene compound selected from the group            consisting of the phosphazene compounds (1) and (2), 50 to            99.9 mol %, and the crosslinked phenoxyphosphazene compound            is free from a free hydroxyl group.

As the phosphazene compound, a phosphazene compound comprising at leastthe above-mentioned (3) crosslinked phenoxyphosphazene compound ispreferred.

In the flame retardant, the ratio (weight ratio) of the phosphazenecompound relative to the phenolic resin (phosphazene compound/phenolicresin) may be about 5/95 to 95/5. The amount of the flame retardant isabout 1 to 100 parts by weight relative to 100 parts by weight of theresin component.

In the resin component, the amount of the styrenic resin is about 0.1 to100 parts by weight relative to 100 parts by weight of the polyalkylenearylate-series resin. The amount of the phosphazene compound is about 30to 1000 parts by weight relative to the styrenic resin, and the amountof the phenolic resin is about 20 to 1000 parts by weight relative to100 parts by weight of the styrenic resin.

The resin composition may further comprise a nitrogen-containingcompound, a carbonizable resin, an antioxidant, a heat stabilizer, adripping inhibitor, a releasing agent, a filler, and others.

The present invention also includes a process for producing aflame-retardant resin composition, which comprises mixing the flameretardant, a polyalkylene arylate-series resin, and a styrenic resin.Moreover, the present invention includes a shaped article formed withthe composition.

BEST MODE FOR CARRYING OUT THE INVENTION

[Resin Component]

The resin component of the present invention comprises a polyalkylenearylate-series resin and a styrenic resin. When a resin componentcomprises a polyalkylene arylate-series resin and a styrenic resin,bleeding out of a flame retardant is inhibited in a flame-retardantresin composition comprising the polyalkylene arylate-series resin andthe flame retardant in combination.

(Polyalkylene arylate-series Resin)

The polyalkylene arylate-series resin includes a homopolyester orcopolyester of an alkylene arylate (e.g., an alkylene terephthalate) asa main component (for example, about 50 to 100% by weight, andpreferably about 75 to 100% by weight). The homopolyester includes, forexample, a poly(1,4-cyclohexane dimethylene terephthalate) (PCT), apolyethylene terephthalate (PET), a polypropylene terephthalate (PPT), apolybutylene terephthalate (PBT), a polyethylene naphthalate (PEN), apolypropylene naphthalate (PPN), and a polybutylene naphthalate (PBN).As a copolymerizable monomer constituting the copolyester, there may bementioned an alcohol component such as a (poly)ethylene glycol, a(poly)trimethylene glycol, a (poly)propylene glycol, a (poly)butyleneglycol, 1,6-hexanediol, and 1,4-cyclohexanedimethanol; a carboxylic acidcomponent such as an aliphatic dicarboxylic acid (e.g., adipic acid,sebacic acid, decanedicarboxylic acid), an aromatic dicarboxylic acid(e.g., isophthalic acid, naphthalenedicarboxylic acid,biphenylenedicarboxylic acid), and a hydroxycarboxylic acid (e.g.,hydroxybenzoic acid, hydroxynaphthoic acid); a phenol component such ashydroquinone, resorcinol, and biphenol; a dihydroxy component such as analkylene oxide adduct of a dihydric phenol component [e.g.,bis(2-hydroxyethoxy)benzene, bis [4-(2-hydroxyethoxy)phenyl]propane];and others. The polyalkylene arylate-series resin(s) may be used singlyor in combination.

The preferred polyalkylene arylate-series resin includes a polyethyleneterephthalate-series resin, a polypropylene terephthalate-series resin,a polybutylene terephthalate-series resin, and the like. In particular,preferred is a polyC₂₋₄alkylene terephthalate (such as a polyethyleneterephthalate and a polybutylene terephthalate), a copolyester (forexample, a polyC₂₋₄alkylene terephthalate/isophthalate copolymer) suchas a polybutylene terephthalate/isophthalate copolymer which comprisesisophthalic acid and the like as a copolymerizable component.

The number average molecular weight of the polyalkylene arylate-seriesresin is not particularly limited, and for example, may be selectedwithin the range of about 5×10³ to 100×10⁴, preferably about 1×10⁴ to70×10⁴, and more preferably about 1.2×10⁴ to 30×10⁴.

The polyalkylene arylate-series resin can be produced by a conventionalmanner, for example, transesterification with the use of an alkyleneglycol, and an aromatic dicarboxylic acid or an ester thereof (e.g.,terephthalic acid or dimethyl terephthalate, and isophthalic acid ordimethyl isophthalate as a copolymerizable component), or directesterification.

(Styrenic Resin)

The styrenic resin includes a homo- or copolymer of an aromatic vinylmonomer, and a copolymer of an aromatic vinyl monomer and at least oneselected from a vinyl cyanide monomer and a rubber component (forexample, a copolymer of an aromatic vinyl monomer and a vinyl cyanidemonomer, a graft copolymer obtained by graft-polymerization of anaromatic vinyl monomer to a rubber component, and a noncrystallinerubber-like polymer obtained by graft-polymerization of an aromaticvinyl monomer and a vinyl cyanide monomer to a rubber component).

Exemplified as the aromatic vinyl-series monomer is styrene, analkylstyrene (e.g., a vinyltoluene such as o-, m-, or p-methylstyrene; avinylxylene such as 2,4-dimethylstyrene; and an alkyl-substitutedstyrene such as ethylstyrene, p-isopropylstyrene, butylstyrene andp-t-butylstyrene), an α-alkyl-substituted styrene (e.g.,α-methylstyrene, α-ethylstyrene, and α-methyl-p-methylstyrene), and thelike. The styrenic monomer(s) may be used singly or in combination.Among others, the preferred styrenic monomer includes styrene,vinyltoluene, α-methylstyrene, and the like. In particular, styrene ispreferred.

As the vinyl cyanide monomer, there may be mentioned, for example,(meth)acrylonitrile. The vinyl cyanide monomer(s) may be also usedsingly or in combination. The preferred vinyl cyanide monomer includesacrylonitrile.

The rubber component includes a conjugated diene-series rubber (e.g., apolybutadiene, a polyisoprene, a styrene-butadiene copolymer, anacrylonitrile-butadiene copolymer, and anethylene-propylene-5-ethylidene-2-norbornene copolymer), an olefinicrubber [e.g., an ethylene-propylene rubber (EPDM rubber), anethylene-vinyl acetate copolymer, and a halogenated polyolefin (such asa chlorinated polyethylene)], an acrylic rubber, and others. Theserubber components may be hydrogenated. The rubber component(s) may beused singly or in combination. Among these rubber components, aconjugated diene-series rubber is preferred. Incidentally, the gelcontent of the rubber component such as the conjugated diene-seriesrubber is not limited at all. Moreover, the rubber component can beproduced by a method such as emulsion polymerization, solutionpolymerization, suspension polymerization, bulk polymerization,solution-bulk polymerization, bulk-suspension polymerization, andothers.

Further, the aromatic vinyl monomer may be used in combination withother copolymerizable monomer. The copolymerizable monomer includes, forexample, a (meth)acrylic ester [e.g., a C₁₋₁₈alkyl ester of(meth)acrylic acid such as methyl (meth)acrylate, ethyl (meth)acrylate,butyl (meth)acrylate, t-butyl (meth)acrylate, hexyl (meth)acrylate,octyl (meth)acrylate and 2-ethylhexyl (meth)acrylate; a hydroxylgroup-containing (meth)acrylate such as 2-hydroxyethyl (meth)acrylateand 2-hydroxypropyl (meth)acrylate; and glycidyl (meth)acrylate], acarboxyl group-containing monomer [e.g., an unsaturated monocarboxylicacid such as (meth)acrylic acid and crotonic acid; an aliphaticunsaturated dicarboxylic acid such as maleic anhydride, maleic acid,fumaric acid and itaconic acid; a monoester of an unsaturateddicarboxylic acid such as a monoester of maleic acid (a monoC₁₋₁₀alkylester of maleic acid such as monomethyl maleate, monoethyl maleate andmonobutyl maleate) or a monoester of fumaric acid corresponding thereto,etc.], and a maleimide-series monomer (e.g., maleimide, anN-alkylmaleimide such as N-methylmaleimide, and N-phenylmaleimide). Thecopolymerizable monomer(s) may be used singly or in combination. Thepreferred copolymerizable monomer includes a (meth)acrylic ester (inparticular, methyl methacrylate), (meth)acrylic acid, meleic anhydride,a maleimide-series monomer, and others.

In the case of using the vinyl cyanide monomer, the ratio (weight ratio)of the aromatic vinyl monomer relative to the vinyl cyanide monomer[aromatic vinyl monomer/vinyl cyanide monomer] is, for example, about10/90 to 90/10, and preferably about 20/80 to 80/20.

In the case of using the rubber component, the ratio (weight ratio) ofthe rubber component relative to the aromatic vinyl monomer [rubbercomponent/aromatic vinyl monomer] is about 5/95 to 80/20, and preferablyabout 10/90 to 70/30. The amount of the rubber component is too small,impact resistance of the resin composition is deteriorated. The amountof the rubber component is too large, dispersion becomes deteriorated sothat the external appearance is apt to be impaired.

In the case of using other copolymerizable monomer, the ratio (weightratio) of the aromatic vinyl monomer relative to other copolymerizablemonomer [aromatic vinyl monomer/other copolymerizable monomer] is about100/0 to 10/90, preferably about 90/10 to 10/90, and more preferablyabout 80/20 to 20/80.

The preferred styrenic resin includes a polystyrene (GPPS), anacrylonitrile-styrene copolymer (AS resin), a high impact polystyrene(HIPS), a graft polymer [for example, an acrylonitrile-butadiene-styrenecopolymer (ABS resin), an acrylonitrile-acrylic rubber-styrene copolymer(AAS resin), an acrylonitrile-chlorinated polyethylene-styrene copolymer(ACS resin), an acrylonitrile-ethylene-propylene rubber-styrenecopolymer (AES resin), an acrylonitrile-butadiene rubber-methylmethacrylate-styrene copolymer (ABSM resin), and methylmethacrylate-butadiene-styrene copolymer (MBS resin)], a block copolymer[for example, a styrene-butadiene-styrene (SBS) copolymer, astyrene-isoprene-styrene (SIS) copolymer, astyrene-ethylene-butylene-styrene (SEBS) copolymer, and astyrene-acrylonitrile-ethylene-propylene-ethylidene norbornene copolymer(AES)], or a hydrogenated product thereof. The particularly preferredstyrenic resin includes a polystyrene (GPPS), astyrene-ethylene-butylene-styrene (SEBS) copolymer, anacrylonitrile-styrene copolymer (AS resin), anacrylonitrile-butadiene-styrene copolymer (ABS resin), and others. Thestyrenic resin(s) may be used singly or in combination.

In the resin component, the amount of the styrenic resin is about 0.1 to100 parts by weight, preferably about 1 to 50 parts by weight, and morepreferably about 1 to 30 parts by weight relative to 100 parts by weightof the polyalkylene arylate-series resin. In the present invention, theresin component comprises the polyalkylene arylate-series resin as amain component.

[Flame Retardant]

The flame retardant of the present invention comprises a phosphazenecompound (e.g., a cyclic phenoxyphosphazene compound, a linear (orchain) phenoxyphosphazene compound, and a crosslinked phenoxyphosphazenecompound), and a phenolic resin. The flame-retardant comprises thephosphazene compound and the phenolic resin so that highflame-retardancy can be imparted to the polyalkylene arylate-seriesresin without deteriorating mechanical properties thereof.

(Phosphazene Compound)

The cyclic phenoxyphosphazene compound includes a compound representedby the following formula (1):

-   -   wherein m denotes an integer of 3 to 25, and Ph represents a        phenyl group.

The linear phenoxyphosphazene compound includes a compound representedby the formula (2):

-   -   wherein X¹ represents the group —N═P(OPh)₃ or the group        —N═P(O)OPh; Y¹ represents the group —P(OPh)₄ or the group —P(O)        (OPh)₂; n denotes an integer of 3 to 10,000; and Ph has the same        meaning as defined in the formula (1).

The crosslinked phenoxyphosphazene compound includes a compound which isformed by crosslinking at least one phenoxyphosphazene compound selectedfrom the group consisting of the cyclic phenoxyphosphazene compound (1)and the linear phenoxyphosphazene compound (2) with a divalentcrosslinking group. Incidentally, when a pair of phenoxyphosphazenecompounds is crosslinked with the crosslinking group, the divalentcrosslinking group is introduced in lieu of a pair of Ph groups.

The divalent crosslinking group includes a phenylene group (o-phenylenegroup, m-phenylene group, p-phenylene group), and a bisphenylene grouprepresented by the following formula (3), and the like. Incidentally,the crosslinking group(s) may be used singly or in combination.

-   -   wherein A represents —C(CH₃)₂—, —SO₂—, —S— or —O—, and a denotes        0 or 1.

The amount of the phenyl group in the crosslinked compound is, based onthe total phenyl groups in the phenoxyphosphazene compound (1) and/orthe phosphazene compound (2), about 50 to 99.9 mol %.

Incidentally, the crosslinked phenoxyphosphazene compound issubstantially free from a free hydroxyl group in a molecule thereof.

The phosphazene compound(s) may be used singly or in combination. Inparticular, a phosphazene compound comprising at least the abovecrosslinked phenoxyphosphazene compound (3) is preferred.

The cyclic and linear phenoxyphosphazene compounds represented by theformulae (1) and (2) can, for example, be synthesized by the methoddescribed in “Phosphorus-Nitrogen Compounds” by H. R. Allcock, publishedby Academic Press, (1972), “Inorganic Polymers” by J. E. Mark, H. R.Allcock, and R. West, published by Prentice-Hall International,Inc.,(1992).

For example, a mixture of a compound of the formula (1) in which thegroup OPh is substituted by a chlorine atom (Cl) and m denotes aninteger of 3 to 25 (a cyclic dichlorophosphazene oligomer), and acompound of the formula (2) in which the group OPh is substituted by achlorine atom and n denotes an integer of 3 to 25 (a lineardichlorophosphazene oligomer) can be obtained by a reaction ofphosphorus chloride (e.g., phosphorus trichloride, phosphoruspentachloride) and ammonium chloride, and if necessary a chlorine (inparticular, in the case of using phosphorus trichloride as thephosphorus chloride) in a chlorine-series solvent (e.g., chlorobenzene,tetrachloroethane). The cyclic and linear phenoxyphosphazene compoundsrepresented by the formulae (1) and (2) can be obtained by substitutinga chlorine atom of the dichlorophosphazene oligomer mixture by phenolwith use of an alkali metal phenolate (e.g., sodium phenolate).

The reaction temperature in a reaction of phosphorus chloride andammonium chloride is, for example, about 120 to 130° C.

If necessary, the mixture of the dichlorophosphazene oligomer may besubjected to purification (e.g., distillation, recrystallization) orpolymerization (ring-opening-polymerization of a cyclicdichlorophosphazene oligomer). By purifying the mixture of thedichlorophosphazene oligomer, a single or sole compound of the cyclicdichlorophosphazene (e.g., hexachlorocyclotriphosphazene,octachlorocyclotetraphosphazene, decachlorocyclopentaphosphazene) can beobtained. Therefore, by substituting the single compound with a phenol,the cyclic phenoxyphosphazene compound such ashexaphenoxycyclotriphosphazene, octaphenoxycyclotetraphosphazene, anddecaphenoxycyclopentaphosphazene can be obtained.

While, a cyclic dichlorophosphazene oligomer is ring-opening-polymerizedto obtain a compound of the formula (2) in which the group OPh issubstituted with a chlorine atom and n denotes an integer of 3 to10,000. Therefore, by substituting the compound with a phenol, thelinear phenoxyphosphazene compound represented by the formula (2) can beobtained.

The ring-opening-polymerization of the cyclic dichlorophosphazeneoligomer can be carried out, for example, by heating to 220 to 250° C.

The crosslinked phenoxyphosphazene compound can be produced bysubstituting (crosslinking) a part of chlorine atoms with an alkalimetal salt of an aromatic dihydroxy compound in lieu of by substitutingall chlorine atoms of the dichlorophosphazene oligomer with an alkalimetal phenolate in the production process of the cyclic phosphazenecompound (1) or the linear phosphazene compound (2).

The dichlorophosphazene oligomer may be used as a mixture of the cyclicdichlorophosphazene oligomer and the linear dichlorophosphazeneoligomer, or each may be used singly. An alkali metal salt of phenol andan alkali metal salt of an aromatic dihydroxy compound may be mixed andsubjected to a reaction. After a reaction of the dichlorophosphazeneoligomer with an alkali metal salt of phenol, an alkali metal salt of anaromatic dihydroxy compound may be reacted with the dichlorophosphazeneoligomer. Moreover, the reaction may be carried out in its reverseorder.

More preferably, a partial-substituted compound in which one part ofchlorine atoms of the dichlorophosphazene compound is substituted with aphenol and one part thereof is substituted with an aromatic dihydroxycompound, and one part thereof is retained as chlorine atom, is obtainedby reacting the dichlorophosphazene compound (e.g., a cyclicdichlorophosphazene oligomer, a linear dichlorophosphazene oligomer), analkali metal salt of a phenol and an alkali metal salt of an aromaticdihydroxy compound (the first stage reaction). Then, thepartial-substituted compound is reacted with an alkali metal salt ofphenol (the second stage reaction) so that the crosslinkedphenoxyphosphazene compound can be obtained. Thus the resultingcrosslinked phenoxyphosphazene compound does not substantially contain afree hydroxyl group since all of hydroxyl groups of the aromaticdihydroxy compound are reacted with dichlorophosphazene compounds.

As the aromatic dihydroxy compound, use can be made of a compound havingone or not less than two benzene ring(s) in its molecule and twohydroxyl groups, more concretely, a compound having the abovecrosslinking group (o-phenylene group, m-phenylene group, p-phenylenegroup, a group represented by the formula (3)). The preferred aromaticdihydroxy compound may include resorcinol, hydroquinone, catechol, abisphenol [for example, a bis(4-hydroxyphenyl)alkane such as4,4′-isopropylidenediphenol (bisphenol-A), 4,4′-sulfonyldiphenol(bisphenol-S), 4,4′-thiodiphenol, 4,4′-oxydiphenol, and 4,4′-diphenol].The aromatic dihydroxy compound(s) may be used singly or in combination.

The alkali metal constituting the alkali metal salt includes sodium,potassium, lithium and the like. The alkali metal(s) may be used singlyor in combination. As the preferred alkali metal, there may beexemplified sodium and lithium.

In the first stage reaction, the total amount of the alkali metal saltof phenol and the alkali metal salt of an aromatic dihydroxy compound isusually about 0.05 to 0.9 equivalent, and preferably about 0.1 to 0.8equivalent based on the chlorine content of the dichlorophosphazeneoligomer. When the amount of the alkali metal salt is significantly lessthan 0.05 equivalent, the degree of crosslinking is insufficient. While,when the amount of the alkali metal salt is remarkably more than 0.9equivalent, a free hydroxyl group (a hydroxyl group at one side of thedihydroxy compound) is introduced into the crosslinkedphenoxyphosphazene compound.

The ratio of the alkali metal salt of the aromatic dihydroxy compoundrelative to the alkali metal salt of phenol is not particularly limited,can be suitably selected within a wide range, and the former/the latteris usually about 1/2000 to 1/4 (molar ratio). When the ratio isremarkably less than 1/2000, the degree of crosslinking is insufficient.While, when the ratio is dramatically more than 1/4, the crosslinkproceeds too much, so that the solubility and meltability of thecrosslinked phenoxyphosphazene compound are deteriorated and thedispersability in a resin is inadequate.

The first stage reaction may be carried out in a solvent (for example,an aromatic hydrocarbon such as toluene, a halogenated aromatichydrocarbon such as chlorobenzene).

The reaction temperature of the first stage reaction is usually in arange from a room temperature to about 150° C.

In the second stage reaction, the amount of the alkali metal salt ofphenol is usually about 1 to 1.5 equivalents, preferably about 1 to 1.2equivalents based on the chlorine content of the dichlorophosphazeneoligomer.

The chlorine content of the phosphazene compound is about not more than2000 ppm (e.g., about 0 to 2000 ppm), preferably about 0 to 1500 ppm,and more preferably about 0 to 1000 ppm in the phosphazene compound.

The amount of the phosphazene compound is, for example, about 0.5 to 60parts by weight, preferably about 1 to 50 parts by weight, and morepreferably about 3 to 45 parts by weight relative to 100 parts by weightof the resin component. Moreover, the amount of the phosphazene compoundis, for example, about 1 to 70 parts by weight, preferably about 1 to 60parts by weight, and more preferably about 5 to 40 parts by weight (inparticular about 10 to 35 parts by weight) relative to 100 parts byweight of the polyalkylene arylate-series resin. Further, the amount ofthe phosphazene compound is, for example, about 30 to 1000 parts byweight, preferably about 50 to 750 parts by weight, and more preferablyabout 100 to 750 parts by weight (in particular about 150 to 500 partsby weight) relative to the styrenic resin.

(Phenolic Resin)

As the phenolic (phenol-series) resin, a variety of resins having aphenol residue as a constituting unit can be used, and include forexample, a novolak resin, an aralkyl resin, a polyvinylphenol-seriesresin, and others. The phenolic resin(s) may be used singly or incombination. Incidentally, if necessary, part or all of phenolichydroxyl groups in the phenolic resin may be changed into a functionalgroup such as a glycidyl ether group, an alkyl ether group, an arylether group, an acyl group (e.g., acetyl group), and an aroyl group(e.g., benzoyl group, toluoyl group), or may be modified with aphosphorus-containing compound such as a phosphoric acid, a phosphorousacid, a phosphoric ester and a phosphite, a boric acid, or an inorganicmetal salt.

(1) Novolak Resin

The novolak resin includes a phenol-novolak resin obtained by a reactionof a phenol [for example, phenol, a phenol having a C₁₋₂₀alkyl group(preferably a C₁₋₁₀alkyl group) as a substituent (e.g., cresol, xylenol,ethyl phenol, propyl phenol, butyl phenol, octyl phenol, nonyl phenol);cyanophenol; and an aryl phenol (e.g., phenyl phenol, benzyl phenol,cumyl phenol)] with an aldehyde (e.g., an aliphatic aldehyde such asformaldehyde, acetaldehyde, and propionaldehyde; an aromatic aldehydesuch as benzaldehyde, and phenylacetaldehyde; in particular,formaldehyde). The phenol-novolak resin includes, for example, a randomphenol-novolak resin which has random methylene bonds to a phenolichydroxyl group, a high-ortho phenol-novolak resin which has manymethylene bonds at ortho position to a phenolic hydroxyl group (e.g., aresin having the ratio ortho/para of not less than 1), and others. Amongthese phenol-novolak resins, a monomerless or dimerless resin havinglower residual phenols is preferred. Moreover, the phenol-novolak resinalso includes an aminotriazine-modified phenol-novolak resin which ismodified or copolymerized with an aminotriazine (for example, melamine,guanamine, acetoguanamine, benzoguanamine). The novolak resin(s) may beused singly or in combination.

The condensation reaction of the phenol and the aldehyde is usuallycarried out in the presence or absence of an acid catalyst such as aninorganic acid (e.g., hydrochloric acid, sulfuric acid) or an organicacid (e.g., p-toluenesulfonic acid, oxalic acid). The ratio (molarratio) of the phenol relative to the aldehyde [the former/the latter] isabout 1/0.6 to 1/1.

(2) Aralkyl Resin

As the aralkyl resin, there may be mentioned a phenol-aralkyl resin or anaphthol-aralkyl resin obtained by a reaction of an aralkyl [forexample, p-xylylene glycol, a p-xylylene glycol C₁₋₄alkyl ether (e.g.,p-xylylene glycol dimethyl ether, p-xylylene glycol dimethyl ether), anacyloxyaralkyl (e.g., p-xylylene-α,α′-diacetate), an aralkyldiol (e.g.,p-xylylene-α,α′-diol), and an aralkylhalide (e.g.,p-xylylene-α,α′-dichloride, p-xylylene-α,α′-dibromide)] with a phenol(e.g., the phenol or alkyl phenol exemplified in the section on theabove-mentioned novolak resin) or a naphthol, an aralkyl resin describedin Japanese Patent Application Laid-Open No. 351822/2000(JP-2000-351822A), and others. The aralkyl resin(s) may be used singlyor in combination.

The phenol-aralkyl resin can be available as trade name “MILEX”(manufactured by Mitsui Chemicals, Inc.), “SUMILITE RESIN PR-54443”(manufactured by Sumitomo Durez Co., Ltd.), “Xylok” (manufactured byAlbright & Wilson Corp.), “MEH7800” (manufactured by Meiwa PlasticIndustries, Ltd.), or others.

(3) Polyvinylphenol-series Resin

The polyvinylphenol-series resin includes a homopolymer of an aromaticvinyl monomer having a hydroxyl group (for example, vinyl phenol,dihydroxystyrene), a copolymer of the above-mentioned aromatic vinylmonomer and other copolymerizable monomer [for example, a styrene suchas styrene, vinyltoluene and α-methylstyrene; a (meth)acrylic acid or aderivative thereof (e.g., an ester, an acid amide) such as (meth)acrylicacid and (meth)acrylic ester, and (meth)acrylonitrile], and others.

The ratio (weight ratio) of the vinyl monomer relative to thecopolymerizable monomer is, for example, about 10/90 to 100/0,preferably about 30/70 to 100/0, and more preferably about 40/60 to100/0 (in particular about 50/50 to 100/0). The preferredpolyvinylphenol includes a vinylphenol homopolymer (apolyhydroxystyrene), in particular a p-vinylphenol homopolymer.

The number average molecular weight of the phenolic resin is notparticularly limited, and for example, may be selected within the rangeof about 300 to 50×10⁴, preferably about 400 to 30×10⁴, and morepreferably about 500 to 5×10⁴.

The amount of the phenolic resin is, for example, about 0.5 to 50 partsby weight, preferably about 1 to 40 parts by weight, and more preferablyabout 3 to 30 parts by weight relative to 100 parts by weight of theresin component. Moreover, the amount of the phenolic resin is, forexample, about 1 to 60 parts by weight, preferably about 1 to 50 partsby weight, and more preferably about 3 to 40 parts by weight (inparticular about 5 to 35 parts by weight) relative to 100 parts byweight of the polyalkylene arylate-series resin. Further, the amount ofthe phenolic resin is, for example, about 20 to 1000 parts by weight,preferably about 20 to 750 parts by weight, and more preferably about 25to 500 parts by weight relative to 100 parts by weight of the styrenicresin.

In the flame retardant, the ratio (weight ratio) of the phosphazenecompound relative to the phenolic resin [the former/the latter] is, forexample, about 5/95 to 95/5, preferably about 10/90 to 90/10, and morepreferably about 20/80 to 90/10 (e.g., about 40/60 to 90/10, inparticular about 50/50 to 90/10).

Since the flame retardant of the present invention comprises a phenolicresin, the flame-retardancy can be imparted to the polyalkylenearylate-series resin with inhibiting the decline in a molecular weightand mechanical properties (e.g., strength, impact resistance) of thepolyalkylene arylate-series resin. In particular, combination use of aphosphazene compound with a phenolic resin ensures impartment of higherflame retardancy to a polyalkylene arylate-series resin compared withuse of a phosphazene compound alone. Moreover, since the flame retardantdoes not contain a halogen, there is no fear of generation of a hydrogenhalide which is poisonous gas upon decomposition or burning, and no fearof mold corrosion or resin degradation involved in the resin molding.

The proportion of the flame retardant (total amount of the phosphazenecompound and the phenolic resin) in the resin composition is notparticularly limited as far as properties of the polyalkylenearylate-series resin are not deteriorated, and is about 1 to 100 partsby weight, preferably about 5 to 90 parts by weight, and more preferablyabout 10 to 80 parts by weight of the flame retardant relative to 100parts by weight of the resin component. When the amount of the flameretardant is too small, it is difficult that the flame-retardancy isimparted to the resin composition. When the amount of the flameretardant too large, mechanical strength of a shaped article obtainedfrom the resin composition and moldability are deteriorated.

[Other Flame Retardant]

The polyalkylene arylate-series resin of the present invention mayoptionally comprise a carbonizable resin, other flame retardant (e.g., anitrogen-containing compound, a phosphorus-series compound, asulfur-containing compound, a silicon-containing compound, an inorganicmetal compound). The above other flame retardant(s) may be used singlyor in combination.

(Carbonizable Resin)

The carbonizable resin includes a resin having an aromatic ring. As suchthe aromatic ring-containing resin, there may be exemplified apolycarbonate-series resin, a polyarylate-series resin, an aromaticepoxy resin (e.g., a biphenol-based epoxy resin, a bisphenol-based epoxyresin, a novolak-based epoxy resin, a phenoxy resin), a polyphenyleneoxide-series resin, a polyphenylene sulfide-series resin, apolyetherimide-series resin. The carbonizable resin(s) may be usedsingly or in combination.

(Nitrogen-containing Compound)

The nitrogen-containing compound preferably includes anitrogen-containing cyclic compound. As the nitrogen-containingcompound, there may be mentioned, for example, a salt of anitrogen-containing cyclic compound having an amino group with acyanuric acid or a derivative thereof, a salt of a nitrogen-containingcyclic compound having an amino group with an oxygen acid (oxyacid), asalt of a nitrogen-containing cyclic compound having an amino group withan organic phosphonic acid or an organic phosphinic acid [for example, amono- to hexamelamine salt of nitrilotris(methylphosphonic acid) (amono- to hexamelamine salt of [nitrilotris(methylene)]tris phosphonicacid), a mono- to tetramelamine salt of1-hydroxyethylidene-1,1-diphosphonic acid; a melam salt, a melem salt,or a melamine.melam.melem double salt corresponding to theabove-mentioned melamine salt], a urea compound (for example,acetyleneurea, a cyclic urea compound such as uric acid), and apolyphosphoric acid amide. Among them, a salt (a) of anitrogen-containing cyclic compound having an amino group with acyanuric acid or a derivative thereof, a salt (b) of anitrogen-containing cyclic compound having an amino group with an oxygenacid (oxyacid) are particularly preferred.

As the nitrogen-containing cyclic compound having an amino groupconstituting the component (a), an amino group-containing triazine, inparticular a 1,3,5-triazine is preferred. For example, there may bementioned melamine, a melamine condensate (e.g., melam, melem, melon),and a guanamine (e.g., guanamine, methylguanamine, acetoguanamine,benzoguanamine, succinoguanamine, adipoguanamine). As a cyanuric acid ora derivative thereof, there may be exemplified cyanuric acid,isocyanuric acid, ammeline, ammelide, and the like. Concretely, the salt(a) of a nitrogen-containing cyclic compound having an amino group witha cyanuric acid includes a melamine salt of a cyanuric acid such asmelamine cyanurate, a melam salt of a cyanuric acid, a melem salt of acyanuric acid, a guanamine salt of a cyanuric acid, and the like. Theproportion of the nitrogen-containing cyclic compound having an aminogroup relative to the cyanuric acid or the derivative thereof is notparticularly limited, and for example, the former/the latter (molarratio) is about 1/2 to 3/1, and more preferably about 1/1 to 2/1.

As the nitrogen-containing cyclic compound having an amino group to beused for the component (b), there may be used a nitrogen-containingcyclic compound similar to the above-mentioned component (a), and thelike. The nitrogen-containing cyclic compound having an amino group isusually preferred to form a salt of at least one amino group which is asubstituent of a ring with oxygen acid. In the case of having aplurality of amino groups, all amino groups may form a salt with oxygenacid. Moreover, a plurality of nitrogen-containing cyclic compoundswhich are the same or different kind (the above-mentionednitrogen-containing cyclic compound, or other nitrogen-containingcompound which contains an amino group) may form a salt with onepolyacid to form a double salt of a polyacid. The oxygen acid includes aphosphoric acid (such as a non-condensed phosphoric acid and a condensedphosphoric acid), a sulfuric acid (e.g., a non-condensed sulfuric acidsuch as peroxomonosulfuric acid and sulfuric acid; a condensed sulfuricacid such as peroxodisulfuric acid and pyrosulfuric acid), a boric acid(e.g., a non-condensed boric acid, a condensed boric acid) and others.Among these oxygen acids, a phosphoric acid (e.g., phosphoric acid,triphosphoric acid, pyrophosphoric acid, polyphosphoric acid) andsulfuric acid are preferred. Specifically, the component (b) includesmelamine phosphate, melamine pyrophosphate, melamine polyphosphate,melam polyphosphate, melem polyphosphate, a melamine.melam.melem doublesalt of polyphosphate, melamine sulfate, melam sulfate, melem sulfate, amelamine.melam.melem double salt of sulfuric acid, and others.

The nitrogen-containing compound(s) may be used singly or incombination.

(Phosphorus-series Compound)

The phosphorus-series compound includes an organic phosphorus-seriescompound and an inorganic phosphorus-series compound. As the organicphosphorus-series compound, an aromatic phosphorus-series compound ispreferred, and there may be mentioned, for example, an aromaticphosphoric ester (e.g., tricresyl phosphate, trixylyl phosphate), anaromatic polyphosphoric ester [for example, a hydroquinone phosphatesuch as a hydroquinone bis(diphenyl phosphate) and a hydroquinonebis(dixylyl phosphate); a resorcinol phosphate such as a resorcinolbis(diphenyl phosphate), a resorcinol bis(dicresyl phosphate) and aresorcinol bis(dixylyl phosphate); a biphenol phosphate such as abiphenol bis(diphenyl phosphate), a biphenol bis(dicresyl phosphate) anda biphenol bis(dixylyl phosphate); a bisphenol-A phosphate such as abisphenol-A bis(diphenyl phosphate), a bisphenol-A bis(dicresylphosphate) and a bisphenol-A bis(dixylyl phosphate); and aphloroglucinol phosphate such as a phloroglucinol tris(diphenylphosphate), a phloroglucinol tris(dicresyl phosphate) and aphloroglucinol tris(dixylyl phosphate)], an aromatic phosphinic ester(e.g., 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide).

Moreover, as other preferred organic phosphorus-series compound, theremay be also mentioned a metal salt of an organic phosphinic acid [forexample, a metal salt (a polyvalent metal salt such as Mg, Ca, Ba, Zn,Al salt) of a di C₁₋₆alkylphosphinic acid, aC₁₋₆alkylC₆₋₁₀arylphosphinic acid, a diC₆₋₁₀arylphosphinic acid andother phosphinic acid].

The inorganic phosphorus-series compound includes a red phosphorus whichmay be coated with a resin, a metal component or the like (e.g., astabilized red phosphorus), a polyphosphate (a salt of a polyphosphoricacid) which may be coated with a resin, a metal component or the like(e.g., an ammonium polyphosphate), a metal salt of a phosphoric acid (ora phosphorous acid) (e.g., an alkaline earth metal salt of a phosphoricacid such as calcium phosphate), a metal hydrogenphosphate (e.g., analkaline earth metal hydrogenphosphate such as calcium orthophosphate),and others.

The phosphorus-series compound(s) may be used singly or in combination.

(Sulfur-containing Compound)

As the sulfur-containing compound, there may be exemplified a sulfuricacid (e.g., a metal salt of a sulfuric acid, a sulfuric ester), asulfonic acid [for example, an organic sulfonic acid (e.g., analkanesulfonic acid such as methanesulfonic acid), a sulfamic acid, anorganic sulfamic acid, or a metal salt thereof, an aminotriazine salt(e.g., melamine, melam, melem; melamine methanesulfonate, melammethanesulfonate, melem methanesulfonate, a melamine.melam.melem doublesalt of methanesulfonate), an ester], and others. The sulfur-containingcompound(s) may be used singly or in combination.

(Silicon-containing Compound)

As the silicon-containing compound, there may be exemplified a zeolite,a (poly)organosiloxane (e.g., a polydimethylsiloxane, apolymethylphenylsiloxane), a branched silicone resin, a layeredsilicate, and others. The silicon-containing compound(s) may be usedsingly or in combination.

(Inorganic Metal Compound)

As the inorganic compound, there may be exemplified a metal oxide (e.g.,molybdenum oxide, tungstic oxide, antimony oxide, zirconium oxide), ametal sulfide (e.g., zinc sulfide, molybdenum sulfide, tungsticsulfide), a metal hydroxide (e.g., magnesium hydroxide, aluminumhydroxide), a metal borate (e.g., hydrous zinc borate, hydrous calciumborate), a metal stannate (e.g., hydrous zinc stannate), and others. Theinorganic metal compound(s) may be used singly or in combination.

The amount of the carbonizable resin and/or other flame retardant may beabout 0 to 100 parts by weight, preferably about 1 to 90 parts by weight(for example, about 1 to 80 parts by weight), and more preferably about3 to 80 parts by weight (in particular about 3 to 60 parts by weight)relative to 100 parts by weight of the resin component.

[Additive]

The polyalkylene arylate-series resin composition of the presentinvention may comprise an additive [for example, a dripping inhibitor,an antioxidant, a stabilizer (e.g., a heat stabilizer(thermostabilizer)), a releasing agent, a filler] if necessary. Theadditive(s) may be used singly or in combination.

The dripping inhibitor includes a fluorine-containing resin such as ahomo- or copolymer of a fluorine-containing monomer and a copolymer of afluorine-containing monomer and other copolymerizable monomer, a layeredsilicate, and others. Concretely, as such a fluorine-containing resin,there may be exemplified a polytetrafluoroethylene, apolychlorotrifluoroethylene, a polyvinylidene fluoride, atetrafluoroethylene-hexafluoropropylene copolymer, atetrafluoroethylene-perfluoroalkylvinyl ether copolymer, anethylene-tetrafluoroethylene copolymer, anethylene-chlorotrifluoroethylene copolymer, and others. The drippinginhibitor(s) may be used singly or in combination.

The antioxidant includes a hindered phenol-series antioxidant [e.g., abranched C₃₋₆alkylphenol such as 2,6-di-t-butyl-p-cresol,2,2′-methylenebis(4-methyl-6-t-butylphenol),2,2′-thiobis(4-methyl-6-t-butylphenol),4,4′-thiobis(6-t-butyl-m-cresol), andpentaerythritol-tetrakis(3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate)];an amine-series antioxidant (e.g., a hindered amine such asnaphthylamine, phenylnaphthylamine, and 1,4-phenylenediamine); aphosphorus-series antioxidant [for example, a phosphite (e.g., abis(C₁₋₉alkyl-aryl)pentaerythritol diphosphite such asbis(2,4-di-t-butylphenyl)pentaerythritol diphosphite, andbis(2,6-di-t-butyl-4-methylphenyl)pentaerythritol diphosphite), and aphosphonite (e.g., tetrakis(2,4-di-t-butylphenyl)-4,4′-biphenylenediphosphonite)]; and others. The heat stabilizer includes an inorganicphosphorus-series stabilizer, for example, a phosphoric acid, aphosphorous acid, a pyrophosphoric acid, a tripolyphosphoric acid, anacidic alkali metal salt of a phosphoric acid (such as sodiumdihydrogenphosphate), an acidic alkaline earth metal salt of aphosphoric acid (such as calcium dihydrogenphosphate, calciumdihydrogenpyrophosphate), and others. The antioxidant(s) and the heatstabilizer(s) may be used singly or in combination.

The releasing agent includes a wax (for example, a C₁₋₄olefinic wax suchas a polyethylene wax, a ethylene copolymer wax and a polypropylenewax), a salt of a higher fatty acid (for example, a metal salt of ahigher fatty acid such as an alkali metal salt of a C₈₋₃₅ fatty acid),an ester of a higher fatty acid (for example, an alkyl ester of a higherfatty acid such as an alkyl ester of a C₈₋₃₅ fatty acid), a higher fattyacid amide (for example, a C₈₋₃₅ fatty acid amide, an alkylene bis fattyacid amide), a silicone-series compound (for example, a silicone oil, asilicone resin), and others. The releasing agent(s) may be used singlyor in combination.

As the filler, there may be exemplified a fibrous filler (e.g., a glassfiber, a milled fiber, a carbon fiber), a particulate filler (e.g., asilicate such as a glass bead, a kaolin and a talc; a metal carbonatesuch as calcium carbonate; a metal oxide such as titanium oxide), aplate-like filler (e.g., a mica, a glass flake, a variety of metalfoil), and others. Among these fillers, the fibrous filler, inparticular the glass fiber (e.g., a chopped strand) is preferred fromthe viewpoint of having high strength and rigidity. The filler(s) may beused singly or in combination.

The filler may be used in combination with a sizing agent orsurface-treatment agent. Such a sizing agent or surface-treatment agentincludes a functional compound. As the functional compound, there may bementioned, for example, an epoxy-series compound, a silane-seriescompound, and a titanate-series compound.

The amount of each additive is, for example, about 0.01 to 20 parts byweight, and preferably about 0.01 to 10 parts by weight relative to 100parts by weight of the resin component. Incidentally, among theadditives, the filler is about 5 to 60% by weight, preferably about 5 to50% by weight, and more preferably about 5 to 45% by weight (inparticular about 5 to 40% by weight) in the flame-retardant resincomposition.

Moreover, if necessary, the resin composition of the present inventionmay comprise other additive, for example, a nucleating agent, alubricant, a plasticizer, a flame-retardant synergist (flame-retardantauxiliary), a stabilizer (a ultraviolet ray absorbing agent, a heatstabilizer), a coloring agent (a pigment, a dye), an antistatic agent, adispersing agent, a compatibilizing agent, an antibacterial agent, andothers.

[Production Process of Flame-retardant Resin Composition]

The flame-retardant resin composition of the present invention may be aparticulate mixture or a molten mixture, and it can be prepared bymixing a polyalkylene arylate-series resin, a flame retardant, and ifnecessary, an additive(s) in a conventional manner.

The resin composition of the present invention can be shaped bymelt-kneading, and molding of a conventional manner such as an extrusionmolding, an injection molding and a compression molding. Thus shapedarticle is excellent in flame retardancy and molding processability(mold-processability), and can be utilized for various purposes. Forexample, the shaped article can be suitably utilized for electric orelectronic device parts, mechanical device parts, automotive parts, andothers.

INDUSTRIAL APPLICABILITY

According to the present invention, use of a flame retardant comprisinga specific phosphazene compound and a phenolic compound in combinationcan impart flame retardancy to the polyalkylene arylate-series resinwithout using a halogen-series flame retardant. In particular, accordingto the present invention, high flame retardancy to the polyalkylenearylate-series resin can be improved without deteriorating properties ofthe polyalkylene arylate-series resin. Further, by blending a smallamount of a styrenic resin, bleeding out of a flame retardant from ashaped article can be significantly suppressed and thermal resistancecan be drastically improved.

EXAMPLES

The following examples are intended to describe this invention infurther detail and should by no means be interpreted as defining thescope of the invention.

In Examples and Comparative Examples, flame retardancy and bleeding outof a flame retardant of the resin composition were evaluated by thefollowing tests. Moreover, in Examples and Comparative Examples, thefollowing polyalkylene arylate-series resins, styrenic resins, flameretardants (phosphazene compounds, phenolic resins), and if necessary,other flame retardants (nitrogen-containing compounds), carbonizableresins, and additives (antioxidants, heat stabilizers, drippinginhibitors, and fillers) were employed.

[Evaluation of Knead-processability (Extrudability)]

A resin composition was subjected to extrusion process with kneading bymeans of a biaxial extruder having a screw size of 30 mmφ, and wasevaluated about knead-processability (extrudability) on the basis of thefollowing criteria.

“A”: blocking and/or surging occurred under the raw material feedhopper, and inhibited stable knead-processing of the resin composition.

“B”: no blocking and surging occurred under the raw material feedhopper, and allowed stable knead-processing of the resin composition.

[Flammability Test]

In accordance with UL94, flame retardancy was evaluated using a testpiece 0.8 mm thick.

[Bleeding Out of Flame Retardant]

A test piece for flame retardant evaluation was put in a Geer oven, andallowed to stand at 150° C. for 4 hours to give a molded piece. Then,bleeding state of the flame retardant was evaluated according to thefollowing five ranks by visually observing the surface of the resultantmolded piece.

-   -   “A”: none    -   “B”: slight bleeding out    -   “C”: moderate bleeding out    -   “D”: much bleeding out    -   “E”: excessive bleeding out

[Color Tone]

A test piece for flame retardant evaluation was put in a Gear pump andallowed to stand at 150° C. for 48 hours. The color tone of the testpiece was visually observed before and after the test, and the change ofthe color tone was evaluated according to the following three ranks.

-   -   “A”: a little change    -   “B”: slight change    -   “C”: significant change

[Tensile Strength (TS)]

A test piece based on ISO 3167 was subjected to an injection molding,and the tensile strength of the molded article was measured inaccordance with ISO 527.

[Thermal Resistance Test (TS Retention)]

A test piece subjected to the tensile test was heat-treated in a Geeroven at 120° C. for 100 days. Thereafter, the tensile strength of theheat-treated piece was measured in accordance with ISO 527. The strengthretention (%) of the heat-treated piece relative to the test piecebefore heat-treating was calculated and evaluated.

[Resin Component A]

(Polyalkylene Terephthalate A1)

-   A1-1: Polybutylene terephthalate [DURANEX, intrinsic viscosity=1.0,    manufactured by Polyplastics Co., Ltd.]-   A1-2: Polybutylene terephthalate [DURANEX, intrinsic viscosity=0.75,    manufactured by Polyplastics Co., Ltd.]-   A1-3: polyethylene terephthalate [BELLPET EFG10, manufactured by    Kanebo, Ltd.]-   A1-4: Polybutylene terephthalate modified with isophthalic acid in    12.5 mole % thereof [intrinsic viscosity=1.0]

(Styrenic Resin A2)

-   A2-1: Acrylonitrile-butadiene-styrene copolymer [CEVIAN VDP611,    manufactured by Daicel Chemical Industries, Ltd.]-   A2-2: Acrylonitrile-styrene copolymer [DIAPET, AS AP-10,    manufactured by Mitsubishi Rayon Co., Ltd.]-   A2-3: Acrylonitrile-styrene copolymer [CEVIAN N JD, manufactured by    Daicel Chemical Industries, Ltd.]

[Phosphazene Compound B]

-   B-1 to B-5: Phenoxyphosphazene compounds obtained from Synthesis    Examples 1 to 5 mentioned below

[Phenolic Resin C]

-   C-1: Novolak resin [SUMILITE RESIN PR-53195, manufactured by    Sumitomo Durez Co., Ltd.]-   C-2: Novolak resin [SUMILITE RESIN PR-53647 (dimerless    phenol-novolak resin), manufactured by Sumitomo Durez Co., Ltd.]-   C-3: Phenol-aralkyl resin [MILEX XL-225, manufactured by Mitsui    Chemicals, Inc.]-   C-4: Polyvinyl phenol [MARUKA LYNCUR M S-1P, manufactured by Maruzen    Petrochemical Co., Ltd.]-   C-5: Glycidyl group-modified novolak resin [EPPN, manufactured by    Nippon Kayaku Co., Ltd.]

[Other Flame Retardant D]

-   D-1: Melamine cyanurate [MC610, manufactured by Nissan Chemical    Industries, Ltd.]-   D-2: Resorcinol bis(dixylylphosphate) [PX200, manufactured by    Daihachi Chemical Industry Co., Ltd.]-   D-3: Melam polyphosphate [PMP200, manufactured by Nissan Chemical    Industries, Ltd.]-   D-4: Zinc borate [Fire Brake ZB, manufactured by US Borax Inc.]

[Carbonizable Resin E]

-   E-1: Bisphenol A-based epoxy resin [EPIKOTE 1004K, manufactured by    Yuka Shell Epoxy K.K.]-   E-2: Polycarbonate [PANLITE L1225, manufactured by Teijin Chemicals    Ltd.]-   E-3: Bisphenol A-based epoxy resin [EPIKOTE 828, manufactured by    Yuka Shell Epoxy K.K.]

[Antioxidant/Heat Stabilizer F]

-   F-1: Pentaerythritol-tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)    propionate] [IRGANOX 1010, manufactured by Ciba-Geigy Ltd.]-   F-2: Bis(2,6-di-t-butyl-4-methylphenyl)pentaerythritol diphosphite    [ADEKASTAB PEP36, manufactured by Adeka Argus Chemical Co., Ltd.]-   F-3: Tetrakis(2,4-di-t-butylphenyl)-4,4′-biphenylene diphosphonite    [SANDOSTAB P-EPQ, manufactured by Sandoz.]-   F-4: Calcium primary phosphate

[Dripping Inhibitor G]

-   G-1: Polytetrafluoroethylene

[Releasing Agent H]

-   H-1: Pentaerythritol tetrastearate [UNISTAR, manufactured by NOF    Corp.]-   H-2: Montanic acid ester [LUZA WAX, manufactured by Toyo-Petrolite    Co., Ltd.]-   H-3: Polyethylene wax [SANWAX, manufactured by Sanyo Chemical    Industries, Ltd.]

[Filler I]

-   I-1: Glass fiber [chopped strand having 13 μm in diameter and 3 mm    long]-   I-2: Glass fiber [chopped strand having 10 μm in diameter and 3 mm    long]-   I-3: Talc [TALC 3A, manufactured by Nippon Talc Co., Ltd.]

Synthesis Example 1 Synthesis of a Cyclic Phenoxyphosphazene Compound(B-1)

Reference: “Phosphorus-Nitrogen Compounds” attributed to H. R. Allcock,Academic Press, (1972).

A toluene solution containing sodium phenolate was added to 20% byweight conc. chlorobenzene solution (580 g) containing 1.0 unit mol(115.9 g) of a dichlorophosphazene oligomer (a mixture of trimer (62% byweight) and tetramer (38% by weight)) with stirring, and the resultantmixture was subjected to a reaction at 110° C. for 4 hours to give acyclic phenoxyphosphazene compound. The content of the residual chlorinewas 0.08% by weight after purification.

Synthesis Example 2 Synthesis of a Phenoxyphosphazene Compound (B-2)

In a 1 L four-neck flask equipped with a stirrer, a thermometer, and areflux condenser were charged 1.3 mol of phenol (123.0 g) andtetrahydrofuran (500 mL), and phenol was uniformly dissolved intetrahydrofuran. Next, 27.6 g of metal sodium was charged in the flaskat a temperature of not higher than 25° C., thereafter the resultantmixture was stirred at 61° C. to 68° C. for 6 hours to prepare a sodiumphenolate solution.

In a 2 L four-neck flask was placed 20% by weight conc. chlorobenzenesolution (290 g) containing 0.5 unit mol (58 g) of a dichlorophosphazeneoligomer (a mixture of trimer (59% by weight), tetramer (12% by weight),pentamer and hexamer (total 11% by weight), heptamer (3% by weight), andoctamer or more (total 15% by weight)). The above sodium phenolatesolution was added dropwise in the flask at a temperature of not higherthan 25° C. with stirring. After the sodium phenolate solution wasadded, the mixture was subjected to a reaction at 71 to 73° C. for 15hours with stirring. After the reaction was completed, the reactionmixture was concentrated, and the concentrate was redissolved in 500 mLof chlorobenzene. Then, the resultant was washed with an aqueoussolution containing 5 wt. % NaOH three times, with 5 wt. % sulfuricacid, with an aqueous solution containing 5 wt. % sodium bicarbonate,and with water twice, and was concentrated to dryness to give alight-yellow wax-like product (108 g).

The GPC analysis of the product showed that the weight-average molecularweight (Mw) was 810 in terms of polystyrene. The TG/DTA analysis of theproduct showed that the melting temperature was 103° C., the initialdecomposition temperature was 330° C., and the temperature at which theweight of the product showed a 5% decrease was 347° C. Moreover, theresidual Cl content (residual chlorine: Hy—Cl) in the product was 0.09%by weight, and the product was identified as the following compound byphosphorus, and CHN elemental analyses.[N═P(—OPh)₂]_(n)

Synthesis Example 3 (Synthesis of a Phenoxyphosphazene Compound (B-3)having a Structure Crosslinked via Metaphenylene)

A mixture containing 1.1 mol (103.5 g) of phenol, 1.1 mol (44.0 g) ofsodium hydroxide, 50 g of water, and 500 mL of toluene was refluxed withheating to remove only water therefrom, thus preparing a toluenesolution containing sodium phenolate.

Concurrently with the above reaction, a mixture of 0.15 mol (16.5 g) ofresorcinol, 1.0 mol (94.1 g) of phenol, 1.3 mol (31.1 g) of lithiumhydroxide, 52 g of water, and 600 mL of toluene was refluxed withheating in a 2 L four-neck flask to remove only water therefrom, thuspreparing a toluene solution containing resorcinol and lithium salt ofphenol. To the toluene solution was added dropwise 20% by weight conc.chlorobenzene solution (580 g) containing 1.0 unit mol (115.9 g) of adichlorophosphazene oligomer (a mixture of trimer (62% by weight),tetramer (12% by weight), pentamer and hexamer (total 11% by weight),heptamer (3% by weight), and octamer or more (total 12% by weight)) at atemperature of not higher than 30° C. with stirring, and the resultantmixture was subjected to a reaction at 110° C. for 3 hours withstirring. The above toluene solution containing sodium phenolate wasadded to the reaction mixture, and the reaction was followed through onat 110° C. for 4 hours.

After the reaction was completed, the reaction mixture was washed with1.0 L of an aqueous solution containing 3 wt. % sodium hydroxide threetimes, then washed with 1.0 L of water three times. Thereafter, thegenerated organic layer was concentrated under a reduced pressure. Theresultant product was subjected to a vacuum drying with heating at 80°C. under a pressure of not higher than 400 Pa for 11 hours to give awhite powder (209 g).

In thus obtained crosslinked phenoxyphosphazene compound, the residualchlorine was 0.08% by weight, the weight-average molecular weight (Mw)was 1080 in terms of polystyrene (based on GPC analysis), thecomposition of the final product was identified as[N═(—O-m-Ph—O)_(0.15)(—O—Ph)_(1.7)] in the basis of the phosphoruscontent thereof and CHN elemental analysis thereof. The TG/DTA analysisof the product showed that the melting temperature was unclear, theinitial decomposition temperature thereof was 304° C., and thetemperature at which the weight of the product showed a 5% decrease was311° C. Moreover, the amount of the residual hydroxyl group wasdetermined as not more than detection limit (not more than 1×10⁻⁶equivalence/g as equivalent weight of the hydroxyl group per gram of thesample) by an acetylation method.

Synthesis Example 4 Synthesis of a Phenoxyphosphazene Compound (B-4)having a Crosslinked Structure via 2,2-bis(p-oxyphenyl)isopropylideneGroup

In a 1 L four-neck flask containing 0.7 mol (65.9 g) of phenol and 500mL of toluene was charged 0.65 gram atom (14.9 g) of a shredded metalsodium under stirring with maintaining the internal temperature of 25°C. After charging the metal sodium, the mixture was stirred for 8 hoursat 77 to 113° C. until complete disappearance of the metal sodium wasobserved.

Concurrently with the above reaction, in a 3 L four-neck flaskcontaining 0.25 mol (57.1 g) of bisphenol-A, 1.1 mol (103.5 g) of phenoland 800 mL of tetrahydrofuran (THF) was charged 1.6 gram atom (11.1 g)of a shredded metal lithium under stirring with maintaining the internaltemperature of not higher than 25° C. After the metal lithium wascharged, the mixture was stirred for 8 hours at 61 to 68° C. untilcomplete disappearance of the metal lithium was observed. To theresultant slurry solution was added dropwise 1.0 unit mol (115.9 g) of adichlorophosphazene oligomer (concentration: 37% by weight,chlorobenzene solution: 313 g, composition: a mixture of trimer (75% byweight), tetramer (17% by weight), pentamer and hexamer (total 6% byweight), heptamer (1% by weight), and octamer or more (total 1% byweight)) for one hour under stirring with maintaining the internaltemperature of not higher than 20° C., and the resultant mixture wassubjected to a reaction at 80° C. for 2 hours. Then, the sodiumphenolate solution which was separately prepared was added to thereaction solution for one hour under stirring with maintaining theinternal temperature of 20° C., and the resultant mixture was subjectedto a reaction at 80° C. for 5 hours.

After the reaction was completed, the reaction mixture was concentratedto remove THF, and another toluene (1L) was added to the mixture. Thetoluene solution was washed with 1 L of an aqueous solution containing 2wt. % NaOH three times, and then washed with 1 L of water three times.Thereafter, the generated organic layer was concentrated under a reducedpressure. Thus obtained product was subjected to a vacuum drying withheating at 80° C. under a pressure of not higher than 400 Pa for 11hours to give a white powder (229 g).

In the crosslinked phenoxyphosphazene compound obtained above, theresidual chlorine was 0.07% by weight, and the composition of the finalproduct was identified as[N═P(—O—Ph—C(CH₃)₂—Ph—O—)_(0.25)(—O—Ph)_(1.50)] in the basis of thephosphorus content thereof and CHN elemental analysis thereof. Theweight-average molecular weight (Mw) was 1130 in terms of polystyrene(based on GPC analysis). The TG/DTA analysis of the product showed thatthe melting temperature was unclear, the initial decompositiontemperature was 308° C., and the temperature at which the weight of theproduct showed a 5% decrease was 313° C. Moreover, the amount of theresidual hydroxyl group was determined as not more than detection limit(not more than 1×10⁻⁶ equivalence/g as equivalent weight of the hydroxylgroup per gram of the sample) by an acetylation method.

Synthesis Example 5 Synthesis of a Phenoxyphosphazene Compound (B-5)having a Crosslinked Structure via 4,4′-sulfonyldiphenylene (bisphenol-Sresidue)

In a 1 L four-neck flask containing 0.4 mol (37.6 g) of phenol and 500mL of THF was charged 0.4 gram atom (9.2 g) of a shredded metal sodiumunder stirring with maintaining the internal temperature of 25° C. Aftercharging the metal sodium, the mixture was stirred for 5 hours at 65 to72° C. until complete disappearance of the metal sodium was observed.

Concurrently with the above reaction, in a 1 L four-neck flaskcontaining 1.70 mol (160.0 g) of phenol, 0.05 mol (12.5 g) ofbisphenol-S and 500 mL of tetrahydrofuran (THF) was charged 1.8 gramatom (41.4 g) of metal sodium at a temperature of not higher than 25° C.After the metal sodium was charged, the mixture was heated up to 61° C.by taking one hour, and the reaction was continued with stirring themixture at 61 to 68° C. for 6 hours to prepare a sodium phenolate mixedsolution. The resultant solution was added dropwise to 20% by weightconc. chlorobenzene solution (580 g) containing 1.0 unit mol (115.9 g)of a dichlorophosphazene oligomer (a mixture of trimer (62% by weight),tetramer (12% by weight), pentamer and hexamer (total 11% by weight),heptamer (3% by weight), and octamer or more (total 12% by weight))under stirring with cooling to a temperature of not higher than ₂₅° C.,and the reaction was carried out at 71 to 73° C. for 5 hours. Then, theabove sodium phenolate mixed solution prepared in advance was addeddropwise thereto, and the reaction was carried on at 71 to 73° C. for 3hours.

After the reaction was completed, the reaction mixture was concentrated,and the concentrate was redissolved to 500 mL of chlorobenzene. Theresultant was washed with an aqueous solution containing 5 wt. % NaOHthree times, with 5 wt. % sulfuric acid, with an aqueous solutioncontaining 5 wt. % sodium bicarbonate, and with water three times, andwas concentrated to dryness to give a light-yellow wax-like product (218g).

In the crosslinked phenoxyphosphazene compound obtained above, theresidual chlorine was not more than 0.01% by weight, and the compositionof the product was identified as almost[N═P(—O-Ph-SO₂-Ph-O—)_(0.05)(—O—Ph)_(1.90)] on the basis of thephosphorus content thereof and CHN elemental analysis thereof. Theweight-average molecular weight (Mw) was 1080 in terms of polystyrene.The TG/DTA analysis showed that the melting temperature was 103° C., theinitial decomposition temperature was 320° C., and the temperature atwhich the weight of the product showed a 5% decrease was 334° C.Moreover, the amount of the residual hydroxyl group was determined asnot more than detection limit (not more than 1×10⁻⁶ equivalence/g asequivalent weight of the hydroxyl group per gram of the sample) by anacetylation method.

Examples 1 TO 18 and Comparative Examples 1 TO 5

With the polyalkylene terephthalate A1 and the styrenic resin A2 wasmixed the phosphazene compound B, the phenolic resin C, other flameretardant D, the carbonizable resin E, the antioxidant/heat stabilizerF, the dripping inhibitor G, the releasing agent H, the filler I, andothers in a proportion described in Table 1 and Table 2, and the mixturewas extruded with a 30 mmφ biaxial extruder [TEX 30, manufactured byJapan Steel Works, Ltd.] at 240° C. (in the case of Examples 1 to 9 and17, and Comparative Examples 1 to 5) or at 270° C. (in the case ofExamples 11 and 18 in which a polycarbonate was added; and in the caseof Examples 10 and 12 to 16 in which a polyethylene terephthalate wasadded) to give a pellet-like composition. The polyalkylene terephthalateresin composition was subjected to an injection molding with a 50 tonmolding machine to form a shaped article for a flammability test, andthe flammability based on UL94, the bleeding out of flame retardant andthe change of the color tone of the shaped article were evaluated.Moreover, the polyalkylene terephthalate resin composition was subjectedto an injection molding with a 80 ton molding machine to form a shapedarticle for a tensile test, and the physical properties (tensileproperties) and thermal resistance (TS retention) were evaluated. Theresultants were shown in Table 1 and Table 2. TABLE 1 Examples 1 2 3 4 56 7 8 9 10 11 12 Polyalkylene A1-1 A1-1 A1-1 A1-1 A1-1 A1-2 A1-2 A1-2A1-1 A1-2 A1-3 A1-2 A1-3 terephthalate 100 100 100 100 100 100 100 100100 70 30 100 100 A1 parts by weight Styrenic resin A2-1 A2-2 A2-2 A2-2A2-2 A2-1 A2-2 A2-1 A2-2 A2-2 A2-2 A2-2 A2-2 A2 parts by 5 5 8 8 5 10 85 5 8 8 5 8 weight Phosphazene B-1 B-2 B-3 B-4 B-5 B-5 B-5 B-5 B-5 B-5B-5 B-5 compound B 20 20 30 30 20 30 30 30 15 30 20 25 parts by weightPhenolic C-1 C-2 C-3 C-4 C-2 C-2 C-2 C-1 C-1 C-2 C-2 C-2 resin C 15 1525 25 15 25 25 25 25 25 10 20 parts by weight Other flame — D-1 D-1 D-1D-1 D-1 D-1 D-1 D-1 D-2 D-3 D-1 D-1 retardant D 7 12 12 7 12 12 12 12 1512 10 12 parts by weight Carbonizable — — — — — — — — — E-1 E-2 — resinE 5 40 parts by weight Antioxidant/ F-1 F-1 F-2 F-1 F-3 F-1 F-1 F-1 F-1F-1 F-1 F-1 F-1 F-4 F-1 Heat stabilizer 0.15 0.15 0.15 0.3 0.3 0.3 0.20.3 0.3 0.3 0.3 0.3 0.3 0.1 0.3 F parts by weight Dripping G-1 G-1 G-1G-1 G-1 G-1 G-1 G-1 G-1 G-1 G-1 G-1 inhibitor G 0.7 0.7 1.2 1.2 0.7 1.21.2 1.2 1.2 1.2 1.0 1.2 parts by weight Releasing — — H-1 H-1 H-1 H-1H-2 H-2 H-2 H-3 — H-2 agent H 1.5 1.5 1.0 1.5 1.5 1.5 1.5 2.5 1.5 partsby weight Filler I — — I-1 I-1 — I-1 I-1 I-2 I-1 I-1 — I-2 parts byweight 80 80 80 80 80 80 80 70 Knead- A A A A A A A A A A A Aprocessability UL94 V-1 V-0 V-0 V-0 V-0 V-0 V-0 V-0 V-0 V-0 V-0 V-0flammability test Bleeding out B B A A A A A A B A A A test of flameretardant Color tone B A A A A A A A A A A A TS (MPa) — — 125 121 — 113123 120 125 130 — 141 TS retention — — 92 90 — 83 83 82 76 93 — 85 (%)

TABLE 2 Examples Comparative Examples 13 14 15 16 17 18 1 2 3 4 5Polyalkylene A1-1 A1-3 A1-1 A1-3 A1-1 A1-3 A1-1 A1-3 A1-4 A1-1 A1-1 A1-1A1-1 A1-1 A1-2 terephthalate A1 50 50 50 50 50 50 50 50 100 100 100 100100 100 100 parts by weight Styrenic resin A2 A2-1 A2-2 A2-3 A2-1 A2-2A2-1 A2-1 — — A2-1 — parts by weight 20 20 20 12 8 8 5 5 Phosphazene B-5B-5 B-5 B-5 B-5 B-5 — B-1 B-1 — B-1 compound B 40 20 40 25 30 30 15 1530 parts by weight Phenolic resin C C-2 C-2 C-5 C-2 C-2 C-2 C-1 — C-1C-1 C-1 parts by weight 5 5 7 25 25 25 15 15 15 25 Other flame D-3 D-1D-2 D-1 D-1 D-4 D-1 D-1 — — — D-1 D-1 retardant D 60 60 20 60 7 5 12 127 12 parts by weight Carbonizable E-1 E-3 — — — E-2 — — — — — resin E 55 10 parts by weight Antioxidant/ F-1 F-1 F-1 F-1 F-1 F-1 F-3 F-1 F-1F-1 F-1 F-1 Heat stabilizer F 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.15 0.15 0.150.15 0.3 parts by weight Dripping G-1 G-1 G-1 G-1 G-1 G-1 G-1 G-1 — G-1G-1 inhibitor G 1.5 1.5 1.5 1.2 1.2 1.2 0.7 0.7 0.7 1.2 parts by weightReleasing H-2 H-2 H-2 H-2 H-2 H-2 — — — — — agent H 1.5 1.5 1.5 1.5 1.51.5 parts by weight Filler I I-2 I-2 I-3 I-2 I-2 I-2 I-2 — — — — I-1parts by weight 110 110 5 110 80 80 80 80 Knead- A A A A A A A B B A Bprocessability UL94 V-0 V-0 V-0 V-0 V-0 V-0 HB HB V-2 HB V-1flammability test Bleeding out A A A A A A A D E A C test of flameretardant Color tone A A A A A A C A C B C TS (MPa) 122 120 123 120 118127 — — — — 112 TS retention (%) 82 80 87 85 83 89 — — — — 70

As apparent from Tables 1 and 2, since the polyalkylene terephthalatesof Examples are excellent in knead-processability with an extruder, aflame-retardant resin composition can be stably produced. A shapedarticle obtained from the flame-retardant resin composition retainsexcellent color tone and excellent thermal resistance without bleedingout of the flame retardant, and high flame retardancy was imparted tothe resin composition.

1. A flame-retardant resin composition comprising a resin component anda flame retardant; wherein the resin component comprises a polyalkylenearylate-series resin and a styrenic resin, and the flame retardantcomprises a phosphazene compound and a phenolic resin, in which thephosphazene compound comprises at least one member selected from thegroup consisting of (1) a cyclic phenoxyphosphazene compound, (2) alinear phenoxyphosphazene compound, and (3) a crosslinkedphenoxyphosphazene compound, as described below respectively: (1) thecyclic phenoxyphosphazene compound

wherein m denotes an integer of 3 to 25, and Ph represents a phenylgroup; (2) the linear phenoxyphosphazene compound

wherein X¹ represents the group —N═P(OPh)₃ or the group —N═P(O)OPh, Y¹represents the group —P(OPh)₄ or the group —P(O)(OPh)₂, n denotes aninteger of 3 to 10000, and Ph has the same meaning as defined in theformula (1); (3) the crosslinked phenoxyphosphazene compound which is acompound formed by crosslinking at least one phenoxyphosphazene compoundselected from the group consisting of the cyclic phenoxyphosphazenecompound (1) and the linear phenoxyphosphazene compound (2) with atleast one crosslinking group selected from the group consisting ofo-phenylene group, m-phenylene group, p-phenylene group, and abisphenylene group represented by the formula (3):

wherein A represents —C(CH3)₂—, —SO₂—, —S— or —O—, and a denotes 0 or 1,and wherein the crosslinking group is bonded to two oxygen atoms withelimination of phenyl groups of the phosphazene compound(s), and thecontent of the phenyl group of the crosslinked compound is, based on thetotal phenyl groups in at least one phosphazene compound selected fromthe group consisting of the phosphazene compounds (1) and (2), 50 to99.9 mol %, and the crosslinked phenoxyphosphazene compound is free froma free hydroxyl group.
 2. A composition according to claim 1, whereinthe phosphazene compound comprises at least (3) the crosslinkedphenoxyphosphazene compound.
 3. A composition according to claim 1,wherein the polyalkylene arylate-series resin comprises at least onemember selected from the group consisting of a polyethyleneterephthalate-series resin and a polybutylene terephthalate-seriesresin.
 4. A composition according to claim 1, wherein the amount of theflame retardant is 1 to 100 parts by weight relative to 100 parts byweight of the resin component.
 5. A composition according to claim 1,wherein the ratio (weight ratio) of the phosphazene compound relative tothe phenolic resin (phosphazene compound/phenolic resin) is 5/95 to95/5.
 6. A composition according to claim 1, wherein the amount of thestyrenic resin is 0.1 to 100 parts by weight relative to 100 parts byweight of the polyalkylene arylate-series resin.
 7. A flame retardantresin composition according to claim 1, wherein the amount of thephosphazene compound is 30 to 1000 parts by weight relative to 100 partsby weight of the styrenic resin, and the amount of the phenolic resin is20 to 1000 parts by weight relative to 100 parts by weight of thestyrenic resin.
 8. A composition according to claim 1, wherein the flameretardant further comprises at least one component selected from thegroup consisting of a carbonizable resin and a nitrogen-containingcompound.
 9. A composition according to claim 1, which further comprisesat least one member selected from the group consisting of anantioxidant, a heat stabilizer, a dripping inhibitor, a releasing agent,and a filler.
 10. A flame-retardant resin composition comprising a resincomponent and a flame retardant, wherein the resin component comprises apolyalkylene terephthalate-series resin and a styrenic resin, the flameretardant comprises a phosphazene compound recited in claim 1 and aphenolic resin, and the amount of the flame retardant is 5 to 80 partsby weight relative to 100 parts by weight of the resin component, theamount of the styrenic resin is 1 to 50 parts by weight relative to 100parts by weight of the polyalkylene terephthalate-series resin, and theratio (weight ratio) of the phosphazene compound relative to thephenolic resin (the former/the latter) is 20/80 to 80/20.
 11. A processfor producing a flame-retardant resin composition, which comprisesmixing a polyalkylene arylate-series resin, a styrenic resin and a flameretardant recited in claim
 1. 12. A shaped article formed with acomposition recited in claim 1.